Your answer is D.
It would not be A or B because Margot was not talking. It said “I said,” which supports my answer.
Hope this helps and ha e a nice day/night!!!
Frederick Douglass wrote an autobiographical slave narrative.
"she" would be the pronoun.
You can rewrite this question as "She is your best friend?"
So in that case, "she" would be the subject.
In English, you just switch around "is" and the subject to make a question and make it sound Englishy
PS in Italian (and probably other languages) you would just say "She is your best friend?"